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HP-35’s x^y Why?
11-03-2021, 02:38 PM (This post was last modified: 11-03-2021 02:51 PM by robve.)
Post: #33
RE: HP-35’s x^y Why?
(11-03-2021 07:47 AM)J-F Garnier Wrote:  Example on Saturn-based HP machines:
125^(1/3) = 4.9999...
but XROOT(125,3)=5 exactly.

Wow. This is even worse, if true:

125^(1/3) = EXP(1/3*LOG(125)) and XROOT(125,3) = EXP(LOG(125)/3) yet somehow these differ on Saturn-based HP machines. Roundoff issues.

This cheap Casio gets it right:

Casio fx-115ES plus
(-128)^(1/7)=-2 OK
(-128)^(.1428571429) ERROR (as can be expected)

- Rob

EDIT: not entirely surprising for the Casio fx-115ES plus, because this model supports exact rationals i.e. 1/3 is exact and 1/(1/3)=3 exactly.

"I count on old friends to remain rational"
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Messages In This Thread
HP-35’s x^y Why? - Matt Agajanian - 10-30-2021, 06:33 PM
RE: HP-35’s x^y Why? - toml_12953 - 10-30-2021, 06:43 PM
RE: HP-35’s x^y Why? - TomC - 10-30-2021, 07:41 PM
RE: HP-35’s x^y Why? - Peet - 10-30-2021, 08:46 PM
RE: HP-35’s x^y Why? - Gerson W. Barbosa - 10-30-2021, 09:54 PM
RE: HP-35’s x^y Why? - Steve Simpkin - 10-30-2021, 11:43 PM
RE: HP-35’s x^y Why? - Peet - 10-31-2021, 07:45 AM
RE: HP-35’s x^y Why? - Steve Simpkin - 10-31-2021, 07:07 PM
RE: HP-35’s x^y Why? - Peet - 10-31-2021, 09:18 PM
RE: HP-35’s x^y Why? - Didier Lachieze - 10-31-2021, 09:49 PM
RE: HP-35’s x^y Why? - lrdheat - 10-31-2021, 12:00 AM
RE: HP-35’s x^y Why? - Steve Simpkin - 10-31-2021, 12:23 AM
RE: HP-35’s x^y Why? - rprosperi - 10-31-2021, 01:09 AM
RE: HP-35’s x^y Why? - Steve Simpkin - 10-31-2021, 01:34 AM
RE: HP-35’s x^y Why? - Dave Britten - 10-31-2021, 01:31 PM
RE: HP-35’s x^y Why? - rprosperi - 10-31-2021, 08:18 PM
RE: HP-35’s x^y Why? - Steve Simpkin - 10-31-2021, 09:39 PM
RE: HP-35’s x^y Why? - rprosperi - 10-31-2021, 11:59 PM
RE: HP-35’s x^y Why? - Steve Simpkin - 11-01-2021, 12:51 AM
RE: HP-35’s x^y Why? - ijabbott - 11-01-2021, 08:40 PM
RE: HP-35’s x^y Why? - EdS2 - 11-01-2021, 09:54 AM
RE: HP-35’s x^y Why? - rprosperi - 11-01-2021, 12:40 PM
RE: HP-35’s x^y Why? - John Keith - 11-01-2021, 02:47 PM
RE: HP-35’s x^y Why? - robve - 11-03-2021, 02:37 AM
RE: HP-35’s x^y Why? - robve - 11-03-2021, 03:46 AM
RE: HP-35’s x^y Why? - Albert Chan - 11-03-2021, 07:45 AM
RE: HP-35’s x^y Why? - robve - 11-03-2021, 01:44 PM
RE: HP-35’s x^y Why? - Albert Chan - 11-03-2021, 03:21 PM
RE: HP-35’s x^y Why? - J-F Garnier - 11-03-2021, 07:47 AM
RE: HP-35’s x^y Why? - robve - 11-03-2021 02:38 PM
RE: HP-35’s x^y Why? - J-F Garnier - 11-03-2021, 03:43 PM
RE: HP-35’s x^y Why? - robve - 11-03-2021, 05:46 PM
RE: HP-35’s x^y Why? - J-F Garnier - 11-03-2021, 06:41 PM
RE: HP-35’s x^y Why? - robve - 11-03-2021, 08:04 PM
RE: HP-35’s x^y Why? - Albert Chan - 11-03-2021, 06:22 PM
RE: HP-35’s x^y Why? - cdmackay - 11-02-2021, 04:22 PM
RE: HP-35’s x^y Why? - ijabbott - 11-02-2021, 08:09 PM
RE: HP-35’s x^y Why? - Gene - 11-02-2021, 04:31 PM
RE: HP-35’s x^y Why? - Jeff O. - 11-04-2021, 09:15 PM
RE: HP-35’s x^y Why? - Guenter Schink - 11-04-2021, 09:21 PM



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